Well worth the investment!
I was very skeptical of this when I bought it. I thought it would be gimmicky and not actually work. But it has been a life saver. I work shifts and have little kids in the house. So I wear earplugs after night shifts and having the onyx band means I never miss my alarm because I can't hear it. My wife is a light sleeper so I always used to wake her up on morning shifts with my alarms. Not anymore! I'm also a really heavy sleeper and this always wakes me up. It doesn't wake you up with a start either. It is a gentle start without being too gentle to not wake you up. The single multifunction button is actually pretty intuitive to use. It is easy to charge, and I normally only charge it once a month. I don't wear it during the day as I don't need it for the steps/calories burnt ect. I don't know how accurate or good it is for that. For what I need it for, this has been great!